Manufacture of compound tubes.



G. H. EVERSON.

MANUFAGTURE or GOMPOUND TUBES.

APPLIOATIOH PILED APB. 7, 1906 904 189. Patented-Nov. 17, 1908.

UNITED STATES PA EN OFFICE.

MANUFACTURE OF COMPOUND TUBES.

Specification of Letters Patent. Application filed April 7, 1906. Serial No. 810,404.

Patenta& Nov.--`17', 1908.

4 burg, in the County of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in the Manufac- Iture of Componnd Tubes, of which the following is a specification, reference being had therein to the accompanying drawing.

Heretofore in the manufacture of compound tubes, that is-tubes lined with brass, copper aluminum, and other netals, it has been necessary to have an outer steel or iron tube of larger diameter than the same tube when finished in order to receive the inner tube, the combined tubes being then rolled down to standard commercial size. In this practice, difliculty is experienced in obtainng tubes of proper initial size as the sizes required are just a little larger than the standards followed by tube manufacturers.

.One object of the invention is to obviate this difliculty by using tubes of standard size, the tubes being expanded in the compounding operation, and then rolled down inthe finishng process to standard size.

A further object is to provide an improved method of manipulating the tubes in the process of initing them, whereby their union is made more positive and the adherence of' one 'to the other more secure than heretofore. In the accompanying drawing, Figures 1, 2, 3 and 4 are views illustrating the several steps of theimproved method.

Referring to the drawing, 2 designates a mandrel formed preferably of high carbon steel, and hence so hard that it need not be tempered to withstand the work. One end of this mandrel is reduced and threaded, as indicated at 3, to receive the detachable bulbshaped expander 4 and securing nut 3. The opposte end of the mandrel is formed with the usual grip-hold 2'. The mandrel is heated by any suitable means and a relatively short and thick tubular billet 5 of brass, copper, aluminum or other lining metal is placed thereon and rolled down to form the inner tube' or lining 6. With the mandrel at a temperature of about 600 degrees Fahrenheit, this rolling down and elongating process is greatly facilitated, as thereby' the lining material is heated and given greater ductility. And furthermore, with the inner tubethus heated it expands more readily within the outer tube as required by a subsequent step of the process. After the. inner mandrel with the inner tube thereon is inserted within outer tube 7 the latter being of standard size. Then with the'expander 4 in position, the assembled tubes and mandrel are arranged in a draw-bench, 8 being the draw head there'of, and the mandrel is withdrawn, as shown in Fig. 3. When being thus withdrawn, bulb 4 expands the inner tube, causing it to tightly f t the outer tube, and the bulb is of such size as, at the same time, to appreciably expand the outer tube 7, thus making its diameter slightly greater than standard. This slight enlargement is eliminated and the compound tube again reduced to standard size by the last ste of the process which consists in inserting a ishing mandrel 9, and rolling the compound tube thereon for the purpose of insuring the union between the outer and inner tubes at all points. The finishing mandrel is preferably heated, a desirable method of heating being that described in Letters Patent grant- Led me June 3, 1902, No. 701,(393. With the finishin mandrel heated, the inner tube is not chil ed, and the contraction of the mandrel when cooling' is suflicient to loosen it and ermit of its ready removal.

I c. aim

1. The method of manufacturing compound tubes consisting in expanding the inner tube into tight engagement with the outer tube and at the same time expanding the outer tube, and then contracting the united and expanded tubes.

pound tubes consistin in rolling the inner tube on a mandrel, %a and mandrel within the outer tube, removing the mandrel and at the same time eX- 'panding the inner tube into engagement with the outer tube, and then rolling the tubes. i

3. The method of manufacturing com- 2. The method of manufacturing com-' 'i tube has been rolled down to proper gage, the

cing the inner tube i pound tubes consisting in rolling the inner tube on a heated mandrel, placing the heated mandrel and the rolled inner tube within the outer tube, removing the mandrel and expandin the inner tube into tight engagement wit the outer tube, and rolling the united tubes.

4. The method of manufacturing compound tubes consisting in rolling the inner tube on a heated mandrel, placing the heated mandrel and the inner tube within the outer tube, removing the mandrel, expanding the her tube in tight engagement with inner tube into `fight engagement with the outet tube and at the same time expanding the outer tube, and then contraet ng the united tubes.

5. The method of manufacturing compound tubes consistin in rolling the imer tube on a heated man rel, lacing the mandrel and inner tube within t e outer tube, removing the mandrel and expandingithe int e outer tube' and at the same time expanding the,

outer tube, and then rolling the united tubes on a heated mandrel' for contracting the same.

In testimony whereof I afix my signature 1.3

in presence of two witnesses.

GEORGE H. EVERSON.

e witnesses:

J NESBIT, ALEX. S. MABON. 

